Abstract

This paper presents nondestructive dark currentmeasurements of tera electron volt energy superconducting linear accelerator cavities. The measurements were carried out in an extremely noisy accelerator environment using a low temperature dc superconducting quantum interference device based cryogenic current comparator. The overall current sensitivity under these rough conditions was measured to be 0.2 nA/Hz, which enables the detection of dark currents of 5 nA.

Received 23 September 2010Accepted 21 November 2010Published online 18 January 2011

Acknowledgments:

This work was supported in part by the Deutsches Elektronen Synchrotron (DESY) Hamburg, Germany. We also thank P. Hanse as well as the company pro-beam AG, Burg, Germany, and the mechanics crew from the MDI group at DESY for their expert assistance in manufacturing most of the mechanical parts for the CCC. Furthermore, we thank HZB for providing the measurement time at the HoBiCaT test facility and their engineers for their help during installation of the CCC in HoBiCaT.